Absorbent articles of this kind are usually made rather thin as compared to their longitudinal and transverse extensions. In order to provide sufficient capacity for storing discharged body fluid, the absorbent material which is included in the article is spread over a large area, which for a diaper extends from the stomach of the user via the crotch region to the waist area on the back of the user.
When a user is standing or sitting the discharged urine ends up in the so called “wetting area”, which is located in the crotch portion of the article, and to avoid local leakage near the wetting area it is important that the article is designed so that liquid is spread quickly over available absorption material. As the distance to the side edges of the article is small as compared to the longitudinal extension of the article, liquid distribution layers are often provided, which distribute liquid in the longitudinal direction of the article. At the same time measures are also often taken to prevent spreading of liquid in the transverse direction out of the article.
In an attempt to prevent lateral leakage, diapers are nowadays provided with so called leg elastics, which hold the side edges of the article in sealing contact against the body. Leg elastics of this kind are described in, for example U.S. Pat. No. 3,860,003. In order to further improve security against lateral leakage it is known to use upright leakage barriers on either side of the crotch region. Leakage barriers of this type are described in, for example EP 0 219 326 B1.
In order to spread liquid in the longitudinal direction of the article from the wetting area, which in substance is the lowest point of the article, liquid must be transported in an upward direction against the effect of gravity. This liquid distribution problem has occupied diaper manufacturers for several decades and a number of different types of wicking layers have been suggested in order to improve liquid distribution in the longitudinal direction.
U.S. Pat. No. 3,017,304 discloses a wicking layer made by wetting one side of an absorbent body of fluff pulp and subsequently compressing the absorbent body, wherein the compression leads to the formation of a compressed wicking layer on the wetted side of the absorbent body. In modern diapers the wicking layer is normally made of compressed chemical fluff pulp.
However no solution has yet been proposed, which provides a sufficiently effective liquid distribution in the longitudinal direction of the article in order to optimally utilize available absorption material. Diapers normally leak laterally long before all absorbent material located at a distance from the wetting area has been utilized. A better utilization of absorbent material in the article is important from economical viewpoint, but also for environmental reasons. If the absorbent material included in a diaper and the like can be better utilized, the amount of absorbent materials needed in the article can be reduced, leading to a smaller need for raw material and a reduction of the waste which originates from used diapers and the like.
One problem with known diapers or the like is that liquid does not spread sufficiently effectively against the force of gravity with the help of a wicking layer. Liquid accumulates in the lowest situated region of the diaper, which is constituted by the wetting area.
WO 00/19955 discloses an absorbent article having wicking barriers preventing radial wicking in the plane of the article and thus promotes central filling of the article with fluid and reduces the likelihood of leaks from the sides of the article.
In WO 00/76447 there is suggested to provide liquid impermeable portions at separate locations of overlapping parts of a wicking layer and liquid storage layers, so as to prevent the transfer of liquid from the wicking layer to the storage layers over said impermeable portions. The impermeable portions are arranged at either sides of a liquid receiving area, so that liquid acquired by said liquid receiving zone is spread in said wicking layer towards the rear and front portions of the article and at a certain distance from the liquid receiving zone is transferred into the storage layers.
However one problem that arises when the wearer, for example the baby, lies down on the stomach, is that the liquid will follow gravity down to the front part of the diaper. This means that the front part of the product gets saturated with liquid, while the back area usually goes on unutilised. The corresponding problem occurs when the wearer lies down on the back, at which the back area of the diaper gets saturated and the front area remains unutilised.